λ/20 fused silica first surface mirror protected aluminum

Product Description

High-Precision λ/20 Fused Silica First-Surface Mirror – 2″ Diameter, 15mm Thick – from a US Defense Space Optics Research Laboratory

Elevate your optics setup with this exceptional, lab-surplus optical flat mirror originating from a US Defense space optics research laboratory, a powerhouse in advanced photonics, laser systems, and defense R&D. This piece reflects the uncompromising precision demanded by the lab’s innovations in electro-optical technologies, making it a collector’s item as much as a functional powerhouse.

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Key Specifications

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Material Advantages – Premium Fused Silica

Fused silica offers exceptional properties for precision optical mirrors :

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Coating Technology – Protected Aluminum with Dielectric Overcoat

Protected aluminum is the most widely used metal coating for visible and near-infrared applications . A λ/2 layer of silicon monoxide (SiO) or silicon dioxide (SiO₂) is applied to protect the delicate aluminum . This overcoat provides abrasion resistance, prevents oxidation over time, and offers a surface that can be carefully cleaned – unlike bare aluminum which should never be touched or wiped .

Key characteristics of this protected aluminum coating :

• Broadband Reflectivity: >92% from 400-1100 nm (visible through near-IR)

• Flat Reflectance Curve: Performance relatively insensitive to wavelength, angle of incidence, and polarization

• Durability: Dielectric overcoat makes the mirror suitable for laboratory and industrial use

• Oxidation Protection: Prevents the aluminum from oxidizing over time

The protective overcoat keeps the aluminum from oxidizing and provides abrasion resistance, making it a popular, low-cost, general-purpose coating for the visible spectrum .

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Rare Qualities – Why This Mirror Stands Out

λ/20 Surface Flatness:
In a market flooded with λ/10 optics, this λ/20 flat is a standout for its nanoscale precision (<32 nm P-V at 633 nm) – twice the accuracy of standard flats. This was crafted to meet US Defense standards where even minor wavefront errors could derail multimillion-dollar projects.

15mm Extra-Thick Substrate:
This premium thickness (compared to standard 6-10mm mirrors) provides:

• Unmatched structural integrity

• Minimal deformation in demanding environments

• Rock-solid stability against vibrations or thermal shifts

• Ideal for high-stakes applications requiring absolute stability

Defense Lab Provenance:
Custom orders for similar specs often wait weeks and cost more than double this price. This mirror is ready for immediate use.

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Applications

Interferometry and Precision Metrology:

• Reference for interferometric testing (e.g., Zygo, Fizeau) in lens polishing, surface profiling, or calibration labs

• Optical flats for flatness verification

Laser Optics:

• Beam manipulation in resonators and alignment systems

• High-energy laser applications requiring perfect wavefronts

• Broadband performance from 400-1100nm suits many common laser lines

Optical Testing and Calibration:

• Autocollimators and wavefront sensors

• Precision alignment tools in labs and manufacturing

• Telescope mirror figuring and quality control

Industrial/Engineering:

• Quality control in semiconductor fabs

• Aerospace simulations and metrology

• Robotics vision systems requiring stable references

Educational:

• Hands-on demonstrations in university photonics courses

• Showcasing real-world lab-grade optics technology

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Condition & Provenance

⚠ HANDLING NOTE: This is a precision optical component with a protected aluminum coating. While the dielectric overcoat improves durability , handle only by edges with clean gloves. Never touch coated surfaces. Store in clean, dry environment when not in use.